Arylsulfonyl halides, such as, for example, benzenesulfonyl chloride, are particularly useful as intermediates in the manufacture of certain biologically active compounds. For example, benzenesulfonyl chlorides can be reacted with primary or secondary amines to produce certain arylsulfonamides such as, for example, N-(beta-O,O-diisopropyldithiophosphorylethyl)benzenesulfonamide.
These arylsulfonyl halides may be produced by any number of methods. For instance, the most commonly employed procedure is the reaction of an arylsulfonic acid with either thionyl chloride or phosphorus pentachloride. Other methods include the reaction of an arylsulfonic acid with thionyl chloride in the presence of a sulfonating agent (U.S. Pat. No. 4,105,692), and the reaction of an arylsulfonic acid with a carbonyl halide in the presence of dimethylformamide and a tertiary amine (U.S. Pat. No. 3,795,705). Another method reacts an arylsulfonic acid with a sulfur monohalide in the presence of excess halogen. The latter method is especially useful in the production of benzenesulfonyl chloride wherein benzenesulfonic acid, sulfur monochloride and chlorine are reacted to produce benzenesulfonyl chloride.
In the processes discussed above, the arylsulfonyl halide produced can be removed by distillation. However, because of the heterogeneous nature of the reaction mixture, the residue which remains after distillation decomposes at such a rapid rate that a safety hazard is presented. Thus, it would be advantageous from both an economic standpoint and a safety viewpoint to inhibit the decomposition of this residue.